SU1081223A1 - Method for producing pelletized material - Google Patents

Abstract

1. METHOD OF MANUFACTURING A PULPED MATERIAL, including feeding crushed bentonite, limestone and fuel to the charge, dosing and mixing, making raw materials with a basicity of 0.3-0.7 and 0.81, 8, the ratio of the amounts ranging from 1 / 9 to 9, mixing raw pellets, loading them on a conveyor marshne and firing at the firing temperature of pellets with basicity H tX4s} 3H i. Tt km.i (,) 4MKjfHOTf: KA 0.3-0.7, characterized in that, in order to reduce capital and operating costs and improve the properties of the finished product, highly basic fibers are made of waterlogged concentrates with the addition of dry finely ground lime; each percent of excess moisture is above its optimal value, and low-base pellets are made from concentrates with optimum moisture. 2. The method according to claim 1, which is based on the fact that high-base oxides are made from hematite, and the low-base ones are made from magnetite concentrates. L 3. Method according to paragraphs. I and 2, that is, the fact that carbon of solid fuel is introduced into pellets in percentage С: СаСОэ 0,078: 1,0.

Description

The invention relates to the preparation of iron ore to metallurgical processing and can be used in the metallurgical industry. A known method for the production of fluxed sinter, including grinding, dosing, mixing of the components of the mixture and sintering. The mixture with a basicity less than 0.8 and more than 2.0 load alternately C1. The closest to the proposed technical essence and the achieved result is a method, the production of agglomerate material, which involves the production of low-core (0.3-0.7 basic) pellets containing 0-1.2% of solid fuel, and highly basic (basicity 0, 8-1.8) oats, containing 1.3–1.5% solid fuel, and after mixing, roasting at a temperature corresponding to the roasting temperature with oats with a basicity of 0.3–0.7 with a ratio of oxyto different basicities from 1/9 to 9 12. However, for the production of o wet moisture (moisture 12-13% difficult to filter flotation concentrates of hematite ores apply pre-drying of the concentrate to a moisture content of 6-8%, which requires the construction of a drying factory with tumble dryers, which causes unnecessary significant capital and operating costs and degrades the quality of raw oats. The aim of the invention It reduces capital and operating costs and improves the properties of the finished product. The goal is achieved by the fact that according to the method of production of agglomerated material, including the supply of ground bentonite, limestone and fuel to the charge, its dosing and mixing, the production of raw materials with a basicity of 0.3-0.7 and 0.8-1.8, the ratio quantities of which range from 1/9 to 9, mixing raw ox papies, loading them on a conveyor machine and firing at a firing temperature of pulps with a basicity of 0.3-0.7, highly basic shells are made of overwetted concentrates with the addition of 8-12% dry lime powder For each. Percent of excess moisture above its optimum level, and low-base minerals are made from concentrates with optimum moisture content. High-grade grades are made from hematite, and low-base grades are made from magnetite concentrates. Carbon solid fuel is introduced into the charge in the ratio of C: CaCOj 0.078: 1.0. As a result of enrichment, along with gaining magnetite, oxidized finely disseminated quartzites, the latter are crushed to 95-100% of the content of particles 44 and even 25 microns (with a specific surface area of 2300-3500). The concentrate of such ores is dehydrated poorly by known technology and contains a higher amount of moisture: 12-14% versus 9-10% of ordinary. Drying part of the concentrate and mixing it with the overwetted one, in addition to significant additional capital and operating costs (for convective discharge of the oxidized concentrate that has been moistened to 13% at the pelletizing plant as part of two OK-520 kiln machines, it is necessary to build a drying plant as part of IZ-) 2 drum dryers size 3, m) leads to a whole complex of difficulties with the use of dried concentrate. When drying, the wet and fine concentrate is granulated, worsening the clodiness of the charge. For efficient mixing of dry and wet concentrates, additional equipment and intermediate warehouses are needed to average moisture, etc. The most favorable blast furnace material is self-melting, i.e. the basicity of 1.0-1.2. However, such basic principles have unfavorable strength properties and their production is unprofitable due to the large number of small dropouts. Thus, from concentrates prepared with such difficulty, it is not possible to obtain blast furnace raw materials of the required quality. The proposed method makes it possible to solve the problem of producing self-melting blast-furnace blast material at a lower cost. For this, excess moisture (3-4%) of the overwetted concentrate (for example, flotation hematite) is reduced to optimal (9-10%) with ca. 1-12% addition of 8–12% limestone to each percentage of excess moisture and raw materials are obtained with increased basicity. From a concentrate with optimum moisture content (for example, magnetite), low-base (0.3-0, raw pellets are obtained and, after natural mixing with overloads and on a roller stacker, raw pellets of both basicities are loaded onto the roasting machine and fired in the optimum mode for low-base pellets. High-base pellets they are softened and form with low-basic, remaining intact, conglomerates possessing in the mixture self-melting gangue and an increased angle of repose in comparison with the known ones.

In order to improve the decarbonization process, solid fuel may be added, crushed separately or mixed with limestone in an amount corresponding to a Ca: CaC02 ratio of 0.078: 1.0. This ratio is due to the need to compensate for the heat consumed externally in the decomposition of calcium carbonate during calcination of the octane,

The method is realized as follows.

At pelletizing factories with individual preparation of the charge for each pelletizer, such as at MGOK, where oxidized and magnetic ores are mined, raw ores can be manufactured with a basicity of 0.3-0.7 per hectare pelletizer, as from a mixture consisting of kz concentrate (for example, magnetite), bentonite and limestone, or a mixture of it with solid fuel. On the other pelletizers, raw oats can be manufactured with a high content of limestone or its mixture with solid fuel from an overmoistened (for example, hematite) concentrate. Moreover, for each percent of excess moisture above the optimum, 8–12% of dry ground lime or its mixture with solid fuel is added so that their basicity is in the range of 2–2.5.

The amount of low basicity of 0.3–0.7 and a lower solid fuel content in the C: CaCO 0.078: 1% ratio can vary in the range of 50–60% of the total amount loaded to the baking sheet. Accordingly, the feeling of the pellets from the higher axis is 2-2.5 and higher is 10 m. fuel, according to the same ratio, may be within.

Bottom of limestone or its contents: mixtures with twister fuel are discharged onto a collecting conveyor, and in overloads from it to the swinging stacker and from the latter to the roller stacker, especially on the roller stacker, are mixed and loaded onto a conveyor baking machine.

A heat-thermal regime is established and maintained on the roasting machine, which ensures the production of low-basicity 0.3-0.7 with high metallurgical properties. At the same time, pellets of higher basicity 2-2.5 are melted and form an agglomerate in an outer layer with a basicity of 0.3-0.7.

PRI mery. Magnetite or hematite concentrates of various ruptures and initial humidity, obtained at the experimental enrichment facility of the Mekhanobrchermet Institute, are mixed in a mixer with an appropriate amount of fine-ground izastnka (or a mixture of it with solid fuel) and bentonite and pelletized in a granulator 01 m. moisture below the optimum is produced with the addition of water to the granulator. The mixing of the oxyggea of highly basic and low-basic in the required ratios is carried out in the same granulator.

They burn the mixture in the burning bowl of 0300 mm in a layer with a height of 400 mm (including 100 mm bed) in a mode that is optimal for low-basic samples.

The results of the tests (Tables 1-3) indicate the feasibility of using the method.

The addition of an average of 10% of dry fine lime for each percent of excess moisture concentrate that is more optimal for pelletizing allows, without costly convective drying, to reduce the moisture content of the charge to acceptable for the production of ok, atyshey. The preparation of a highly basic mixture of hematite concentrates solves two problems: reduction of moisture without special drying of the concentrate and improvement of the metallurgical properties of the finished product.

In tab. Table 1 shows the results of dewatering the overwetted concentrate by adding dry ground lime (0% for each percent of excess moisture above the optimum), in Table. 2 - properties of calcined mixtures of agglomerate and pellets from magnetite and hematite (denominator) concentrates, in Table, 3 - comparative properties of mixtures of agglomerate and pellets according to known and proposed methods.

Table 1

The addition of limestone (basicity) in the mixture of dry,%

highly basic

low-base,% (ed.)

The total basicity of the mixture, ed.

The ratio of the basicities in the mixture

Properties of mixtures of magnetite hematite pellets

Grading , %

sintered agglomerate pieces with pellets (+20 mm)

single octane (5–16 mm)

13 (2.6) 27 (2.2) 380.9

1.5 (0.3) 6 (0.5)

U (0.7)

1.2

1.2

High to low as 40: 60%

18.7 / 22.0 22.8 / 49.9 31.1 / 55.7

76.0 / 73.9 72.2 / 45.2 63.7 / 41.0

Drum sample,% +5 mm

-0.5 mm

Sample after recovery,% +5 mm

-0.5 mm

Corner of natural rtcofca

The basicity of the mixture is okay, d.ed.

Granulometric composition of the finished product,%

pieces of agglomerate with pellets

individual pellets

trivia (- 5 mm

93.3 / 93.991.8 / 96.492.6 / 95.2

5.1 / 5.04.4 / 3.24.6 / 4iO

70.7 / 75.277.0 / 80.376.5 / 88.1

8,7 / 6,15,4 / 5,04,5 / 2,6

31/32

31.5 / 3332/34

Table3

1.2

49.9

45.2 4.9

Drum sample,%

+5

-0.5 mm

Sample after recovery,%

+5 mm

-0.5 mm

Angle of repose

96.4 3.2

80.3 5.0

33

Claims (3)

1. METHOD FOR PRODUCING GLASSED MATERIAL, including the feeding of crushed bentonite, limestone and fuel into the mixture, its dosing and mixing, the manufacture of raw pellets with a basicity of 0.3-0.7 and 0.81.8, the ratio of quantities of which is from 1/9 up to 9, mixing raw pellets, loading them onto a conveyor machine and firing at a firing temperature of pellets with basicity 0.3-0.7, characterized in that, in order to reduce capital and operating costs and improve the properties of the finished product, highly basic pellets are made from waterlogged concentrates with the addition of 8-12% dry fine-grained limestone for every percentage of excess moisture above its optimum value and low-base pellets are made from concentrates with optimal humidity. 2. The method according to p. ^ Characterized in that highly basic pellets are made from hematite, and low-basic pellets are made from magnetite concentrates. 3. The method according to PP. 1 and 2, with the fact that the carbon of solid fuel is introduced into the pellet mixture in a percentage ratio of C: CaCO ₃ = O, O78: 1.0. SU .. „1081223